--- In dmcnews@xxxxxxxxxxx, "DMC Joe" <dmcjoe@xxxx> wrote: > Walt, > > Your problem is more that likely related to a problem in the acceleration enrichment circuit. This is a very common problem in the CIS fuel injection system. If there is a problem in the Acceleration enrichment circut , how can I find out which part is the problem? I also replaced the CPR unit last month, run well for 3 weeks but now the problem come back again--- hesitste when it's cold. Sometime it accelerate and idle fine at the first minute , but after that it'll start to idleing rough and hesitste. (drop to around 500rpm and then rev up to1000 ).If the CPR unit is bad, why the engine can accelerate fine at first one to two minutes? Thanks. Simon